invagination
noun
in·vag·i·na·tion in-ˌva-jə-ˈnā-shən 
1
: an act or process of invaginating
specifically : the formation of a gastrula by an infolding of part of the wall of the blastula
2
: an invaginated part
Example Sentences
Recent Examples on the Web In 2010, Seely, who was a member or the Arizona State University triathlon team when she was diagnosed with Chiari II Malformation, basilar invagination, and Ehlers-Danlos Syndrome, which affect her brain, spine, and connective tissues. 
Madison Thacker, The Arizona Republic, 2 Oct. 2021
Madison Thacker, The Arizona Republic, 2 Oct. 2021 Word History
First Known Use
circa 1658, in the meaning defined at sense 1
Medical Definition
invagination
noun
in·vag·i·na·tion -ˌvaj-ə-ˈnā-shən
1
: an act or process of invaginating: as
a
: the formation of a gastrula by an infolding of part of the wall of the blastula
b
: intestinal intussusception
2
: an invaginated part